Unlike other ethnic groups who attribute their origin to a single country, Hmong Americans originate from the mountainous regions at the confluence of Vietnam, Cambodia, and Laos. The U.S. government resettled Hmong who escaped from Southeast Asia to California and the Midwest. At the time of migration, the Hmong were pre-literate, believed in animism, and were accustomed to an agrarian lifestyle. Our latest California data indicate that the age-adjusted male incidence rate for liver cancer for Hmong is 25.7/100,000 compared to 3.7/100,000 for non-Hispanic white males and 8.8/100,000 for female Hmong compared to 1.5/100,000 in non-Hispanic White females. The purpose of this study is to increase the hepatitis B serological testing for Hmong adults and secondarily to increase their knowledge levels of hepatitis B and liver cancer. Over the five year research tudy, we propose to: (1) measure the baseline proportion seroloically tested for hepatitis B [HBV] among Hmong, ages 18-64, in the Greater Sacramento Area;(2) Develop an intervention using lay health workers to promote serological testing for HBV and increase knowledge of HBV among Hmong adults;(3) Evaluate the effectiveness of the lay health worker intervention by conducting a randomized, controlled trial among Hmong adults aged 18-64 not previously tested for HBV;and (4) Characterize facilitating and impeding factors associated with serological testing for HBV among Hmong adults. To achieve these Aims, universitybased researchers will work collaboratively with Hmong bilingual interviewers, community leaders, and agencies in conducting a baseline assessment of serological testing among Hmong and follow with randomizing those who have not been serologically tested for HBV into intervention or control conditions. We shall use the Health Behavior Framework to guide our study and the lay health worker teams as the intervention agents . Intervention effectiveness will be based on the basis of self-reported serological testing rates that will be also verified through medical records check. We have detailed the training and evaluation of lay health workers and have incorporated rigorous safeguards to minimize contamination. As a consequence of this study, we expect data on the empirical effectiveness of a lay health worker intervention model for increasing serological testing for HBV and that the burden of HBV-induced liver cancer reduced.